Swivel fluid fittings of the prior art are of two basic types: the pressure balanced type which requires two rotary seals, and the pressure unbalanced type which requires only one rotary seal but which requires a ball thrust bearing in order to minimize the torque that is required to rotate the fitting at high fluid pressures. The pressure unbalanced type has the advantage of compactness and freer fluid flow than the pressure balanced type.
The prior art in the pressure unbalanced type of swivel fluid fittings has included the assembly gland type in which the thrust bearing is longitudinally inserted and retained by an assembly gland. This type of swivel fluid fitting is inherently complex, bulky, and expensive.
The prior art in pressure unbalanced swivel fluid fittings has also included a design in which grooves for thrust bearing races are machined into mating surfaces of the inner and outer members and the thrust balls are inserted individually through a transversely disposed hole that is subsequently plugged. This type of swivel fluid fitting is less complex, less bulky, and less expensive than the assembly gland type.
The present invention retains all of the advantages of the last-mentioned type of swivel fluid fitting; and, in addition, both eliminates the transversely disposed hole and locates the rotary shaft seal outwardly of the thrust balls whereby the thrust balls are lubricated and protected from corrosion by the oil being conducted by the swivel fluid fitting.